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Showing 1 to 20 of 26 for “"Elasmobranch"”.
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Aerobic and anaerobic activity metabolism of an elasmobranch
… to anthropogenic or environmental stressors. Elasmobranchs, in particular, represent some of the most exploited vertebrate taxa on the planet, and many species are data deficient with regard to a basic understanding of energetics or how stressors alter patterns of energy use and allocation. …
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Detection, Activity Measurement and Phylogeny of Ureolytic Bacteria Isolated from Elasmobranch Tissue
<p>Free-ranging marine elasmobranch tissue-associated micro-organisms were cultured from free-ranging Atlantic stingray (<em>Dasyatis sabina</em>) and Atlantic sharpnose sharks (<em>Rhizoprionodon terraenovae</em>). 16S rRNA gene phylogeny indicated bacteria community structure in both …
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Exploring the Glucocorticoid Actions of 1α-Hydroxycorticosterone (1α-OH-B) in the Elasmobranch Fishes
… (1α-OH-B) is unique to the elasmobranch fishes. It is thought that 1α-OH-B acts as both the primary glucocorticoid (GC) and mineralocorticoid (MC) in these fishes, a dual role analogous to that of cortisol in the teleost fishes. The MC characteristics of 1α-OH-B are well …
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The Elasmobranch-Microbe Relationship: Trimethylamine n-oxide Synthesis, Urea Hydrolysis, and Microbe-Osmolyte Interactions in the Atlantic Stingray, <i>Dasyatis sabina</i>
<p>The elasmobranch osmoregulatory strategy is predicated on the accumulation of nitrogenous compounds, primarily urea and trimethylamine n¬-oxide (TMAO). Despite the abundance of these plasma osmolytes, it is notable that elasmobranchs appear to lack urease and TMA oxidase (Tmase), enzymes that …
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Inner ear morphology in elasmobranchs: implications for auditory capacity and ecology
Elasmobranchs (sharks, rays, and skates) represent the majority of Chondrichthyan species, a clade of cartilaginous fishes that first appeared over 400 million years ago. Given their basal position in the evolutionary tree of gnathostomes, elasmobranchs can provide key insights into the early …
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e(lasmo)DNA : the role of environmental DNA (eDNA) analysis in marine fish biodiversity assessment, with special focus on elasmobranchs
… strategies for taxa like teleosts and elasmobranchs, depends on the accurate assessment and monitoring of the distribution and abundance of target species. However, detecting species occurrences is often even more challenging in the aquatic environment than on land. Consequently, as is …
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Characterization of Andrenocortical Tissue Morphology, Histology, and Steroid Synthesis Among Finetooth (<i>Carcharhinus isodon</i>), Blacktip (<i>Carcharhinus limbatus</i>), Atlantic Sharpnose (<i>Rhizoprionodon terraenovae</i>), and Bonnethead (<i>Sphyrna tiburo</i>) Sharks
… balance. Previous research characterizing the elasmobranch interrenal suggests that the number of interrenal bodies that produce the single primary corticosteroid, 1a-hydroxycorticosterone (1a-OHB), varies among species. However, potential species-specific differences in the amount of …
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Integrated approaches for monitoring sharks: Leveraging machine learning, big data, and molecular biology
… A preliminary multi-species assay detected 12 elasmobranch species. These workflows provided novel spatiotemporal insights into white shark (and other elasmobranch) occurrence in hypothesized hotspots. Together, these chapters demonstrate how integrated computational and molecular approaches …
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Factors influencing the development and mortality rate of shy and cat shark embryos in South African waters
… we can further understand the nature of elasmobranch reproductive behaviour, including embryo growth and development. Two Scyliorhinid species endemic to South African waters are investigated here, Poroderma pantherinum, commonly known as the Leopard catshark and Haploblepharus pictus the …
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Studies on the osmotic and ionic regulation of the striped dogfish Poroderma africanum (Gmelin)
… relationship to external conditions, in a local elasmobranch species. The topic has been extensively examined in some overseas countries hut so far very little physiological work on the osmoregulation of marine elasmobranchs has been carried out in the South African region. The species chosen was …
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Aspects of the biology of Trypanorhynch tapeworms and investigations on their use as biological tags
… research on trypanorhynchs found in over 1,000 elasmobranch and teleost fish. This led to a choice of three research topics for more detailed investigations: (i) taxonomic studies on four little-known species and the application of this information to fisheries biology, (ii) life-cycle studies …
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Occurrence and genetic diversity of lemon sharks (Negaprion brevirostris) at a nursery ground at the Chandeleur Islands, Louisiana.
… to classify the Chandeleur Islands as an elasmobranch nursery ground under the definition presented by Huepel <em>et al. </em>(2007). Current literature and high densities of <em>N. brevirostris </em>suggests that the Chandeleur Islands are the only area in the northern Gulf of Mexico …
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Regulation of Glucose Uptake and Transporter Expression in the North Pacific Spiny Dogfish (Squalus suckleyi)
Elasmobranchs (sharks, skates, and rays) are a primarily carnivorous group of vertebrates that consume very few carbohydrates and have little reliance on glucose as an oxidative fuel, the one exception being the rectal gland. This has led to a dearth of information on glucose transport and …
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Functional and Molecular Aspects of Xenobiotic Transport in Choroid Plexus
… was studied in a mammalian (rat), a comparative elasmobranch and in the in vitro porcine CPEC culture model, using the model compound fluorescein-methotrexate (FL-MTX). FL-MTX transport was shown to be a specific and concentrative, Na+-dependent and metabolism-dependent two-step process. Finally, …
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DNA+eDNA: integration of traditional and emerging tools for monitoring marine ecosystems
… and variability of two commercially important elasmobranch species using nuclear DNA markers. These studies provide foundational data for monitoring population dynamics and assessing the effectiveness of fisheries management. In conclusion, this thesis integrates traditional and innovative …
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Incorporating Migration and Local Movement Patterns into Management Strategies for Spiny Dogfish (Squalus acanthias)
… behaviors associated with a highly migratory elasmobranch species. In particular, I seek to determine whether sufficient evidence exists to warrant the separation of the northwest Atlantic Spiny Dogfish (Squalus acanthias) into separate management units. These management units are not …
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Decoding the Little Skate Retina: Structural Variants and Developmental Dynamics
<p>The retinal development of Elasmobranchs (the superclass comprising sharks, skates and rays) is a poorly understood phenomenon, but it represents a critical component of the broader picture of vertebrate visual development. Evolutionary divergence between these organisms and the mammals is vast, …
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Decoding the Little Skate Retina: Structural Variants and Developmental Dynamics
<p>The retinal development of Elasmobranchs (the superclass comprising sharks, skates and rays) is a poorly understood phenomenon, but it represents a critical component of the broader picture of vertebrate visual development. Evolutionary divergence between these organisms and the mammals is vast, …
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The ecology of ray species in an urbanised estuary: Seasonality, habitat use and pollutant exposure in Tauranga Harbour
… movement behaviour in non-shark-like batoid elasmobranch species was carried out, as optimisation of tagging research technique underpins the ability to track behaviour of these organisms for long periods. Most studies reviewed adopted tag anchor techniques used on teleost fishes or sharks. …
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Evolution of the structure and function of vertebrate brain gonadotropin-releasing hormone
… occurring in vertebrates as diverse as birds and elasmobranch fish. In dogfish (Poroderma africanum) brain seven factors, which stimulated release of LH from chicken dispersed anterior pituitary cells, were separated on analytical HPLC. Two of these factors were partially characterized as …
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